Electrostatic separation.



No. 653,343. Pate nt'ed My ID, I900.

E. GATES. ELECTROSTATIC SEPARATION.

(Application filed Dec. 2, 1899.)

(No Model.)

*UNITED STATES,

PATENT OFFICE.

ELMER GATES, OF CHEVY CHASE, MARYLAND, ASSIGNOR To THEODORE J'.

MAYER, or. WASHINGTON. DISTRICT or COLUMBIA.

" ELECTROSTATIC SEPARATION.

SPECIFICATION forming part of Letters Patent No. 653,343, datedd'uly' 10, 1900.

' Application filed. December 2,1899. steam. 739,006. (No specimens.)

To all whom it mag concern:

Be it known that I, ELMER GATES, a citizen of the United States,residing at Chevy Chase, in the county of Montgomery, State of Maryland, have invented certain new and useful Improvements in Electrostatic Separation;

and I do'hereby declare the following to be a -full, clear, and exact description of the inwention, such, as will enable others skilled in the art to which it appertains to make and use the same.

nan application for Letters Patent of the United btates filed by me September 26, 1899,

Serial No, 731,762, I. have described and tion by charging the moving'particles electroclaimed a method for separating diamagnetic particles from la mixture containing the same by causing said particles to travel from, an

intense part of a magnetic .field into a relatively-weakpart thereof, and in an application filed of even date herewith, Serial No.

739,007, I have described and claimed -a method of intensifyingsaid diamagnetic acstat-ically.

My present invention concerns itself wholly with electrostatic separation-z. e. ,separation due wholly to the, action of electrostatic charges upon the moving particles of the mi5rture treated. It is well known that all substances, if insulated, may be electrified and that the insulators or idioelectrics or nonconductors may by rubbing be caused to develop a noticeable charge of electricity. Insulators are such substances as amber, sulfur,

resin, shellac, glass, silk, sand, &c. Another class, called anelectrics or conductors,

, consists mostly of metals. If uninsulated, a

metal does not hold its charge of electricity, it being rapidly discharged or conducted away. If, however, a metal be insulated, an electrostatic charge may be readily imparted" to it and will be retained thereby. I have found that when a falling stream ct pulverized substances containing a mixture of anelectrics (or conductors) and idioelectrics '(or nonconductors) is subjected to an el .trostatic charge these substances-become electrified to different degrees andare di e'rently at this discovery for the practical separation of said substaneesas, for instance, the separation of particles of gold from'placer-sa'nd in which they are contained.

resented an apparatus adapted for the practice of myinvcntion.

supply-hopper provided with an exit-apertureadapted to. permit'a stream of placer-sand "quarter inch aperture for a distance of eight: eeninches to certain lower hoppers or receptaeles B G D. The upper receptacle is pro- Jlinings b c d. E indicates the positive pole of astatic machine arranged in proximityto the falling stream ofplacer-sand from the hopper A, and F F represent terminals or electrodes for supplying an electrostatic charge to the falling stream through the intermediacy of the metallic linings of the upper and lower hoppers, as indicated. Urder these circumstances by the employment of Leyden jars in tension in connection with an eighteen-inch ten-plate static machine, so as to get. the equivalent of a three-foot spark, the mixturewill be repelled from the vertical path; but the particles of gold will be repelled much farther than the particles of sand, which latter are in reality but slightly aflzected. I prefer to locate the terminal E midway between the upper and lower hoppers, for the reason that that is the lo'cation of approximately no polarity with reference to the upper and lower hoppers. The sand hopper from the insulating, medium of the the upper hopper and are repelled bythe pole or terminal ,E, the repulsionpf the metal particles being 'sufficient to divert the ,hopper or receptacle 0 as tailings, the repulsion of the latter being practically negligible.- If the pole or terminal Eis charged negatively instead of positively, it will attract the particles and will attract the me vided with a metallic lining a; and the lower receptacles are provided with like metallic them from the main stream or flow andcanse them to drop into the hopper B- as heads, while the particles of sand drop into.

In the accompanying drawing I have rep.-

Referring to the drawing, A represents a containing-particles of gold to fall from a and metal particles falling from the upper;

9 air retain the charge which they acquired in tallic particles to the greater degree, so that the latter will be diverted into the receptacle D, the particles of sand dropping into the,

hopper or receptacle 0, as before.- I have 5 found it immaterial to successful separation by this method whether the upper-receptacle be connected to the positive terminalbf the source of high-tension static electricity and the lower receptacles be connected to the to negative terminal thereof or whether the upper hopper be connected with the negative terminal and thelower hoppers or receptacles 4 be connected to the positive terminal.

Having thus described my invention, what i 5 I claim is'- 1. The method of separating from a mixture particles of relatively-greater electrostatic capacity than the remainder, which consists in passingthe mixture through a 20 field of convective discharge of static electricity, thereby chargingsaid mixture electrostatically, and diverting the particles of greater electrostatic capacity by causing the electrified mixture to pass through another '25 field of convective discharge of static electrieity, the direction of whose lines of force intersects that of ,the first, substantially as described. V

2. The method of separating from a mix ture particles of relatively-greater electrostatic capacity than the remainder, which consists in passing the mixture through a field of convective discharge of static electricity, thereby charging said mixture electrostatieally aud diverting the particles of greater electrostatic capacity by causing the electrified mixture to pass through another field of convective discharge of I static ele'ctricity, the direction of whose lines of force intersects that of; the first, and whose discharge-terminal is located midway between the terminals of the first, substantially as described. a

In testimony whereof I allix my signature in presence of two witnesses' ELMER GATES.

Witnesses:

THEODORE J. MAYER, Hum; M. STERLING. 

